Hemodialysis apparatus for artificial kidneys generally comprises a supported, semi-permeable membrane made of a cellophane-type material, positioned in a casing to provide a blood flow path along one side of the membrane and a dialysis solution flow path along the other side, for diffusion exchange across the membrane between the blood and the dialysis solution without the direct intermixing of the two liquids.
In the actual hemodialysis process, a considerable number of processing steps are required during the operation for bringing the blood to the hemodialyzer, and withdrawing it from the hemodialyzer for return to the patient. In the presently-conventional arterial and venous sets which are used to withdraw blood from a patient, convey it to the dialyzer, and return it again to the patient, bubble traps, filters, sterile access sites for injection needles, and access sites for pressure monitor equipment may all be included on the sets, which primarily comprise flexible, blood compatible plastic tubing. Accordingly, in the present technology of dialysis, two different and separate long, tubular sets are utilized, the arterial set upstream from the dialyzer in terms of blood flow, and the venous set downstream from the dialyzer.
Hence, to set up a dialysis procedure, a dialyzer must be selected, and the nurse must also separately obtain an arterial set and a venous set. The packaging of all of these devices must be opened, and the devices repsectively must be connected and assembled together, with other auxiliary equipment being also added to the system. This requires the services of a highly trained technician, who must make a considerable number of connections between the sets and the dialyzer, flawlessly and without error.
In accordance with this invention, a one-piece hydraulic circuit is provided to replace many of the functions of the arterial inlet and outlet sets, and auxiliary equipment. The one-piece hydraulic circuit may be connected to the dialyzer itself at the time of manufacture, if desired. The set-up of the dialysis system prior to use is thus greatly simplified, eliminating many of the connections which must be made by the technician at the site of use, which, in turn, reduces the possibility of error, and contamination of the system during the assembly and connection process. Furthermore, the system of this invention is compact and simplified, saving a considerable amount of valuable space around the bed during the dialysis procedure.